• 한국기계가공학회지
• /
• 제18권9호
• /
• pp.44-51
• /
• 2019

Three types of samples with defects were measured by lock-in med-IR (infrared) thermography with various lock-in frequencies for different materials. The lock-in method can be used to detect defects when an external energy source is applied to the object, the non-uniformity of the incident thermal energy distribution is eliminated, and the camera's measurement cycle is synchronized with the load cycle of the incident energy source. For inspecting samples with defects, results of thermal images are analyzed when three types of materials, i.e., SM45C, STS316L, and AL6061 are tested and three lock-in frequencies, i.e., 0.08, 0.1, and 0.12 Hz are applied. In this study, the optimal lock-in frequencies were determined by comparing the results of each material and lock-in frequency measured using the mid-IR camera.

• 한국정보통신학회논문지
• /
• 제21권11호
• /
• pp.2037-2042
• /
• 2017

스마트 공장은 미리 입력된 프로그램에 의해 생산시설이 수동적으로 움직이는 공장 자동화 작업 방식과는 달리, 생산 설비 스스로 작업 방식을 결정하여야 한다. 생산 설비 스스로 작업 방식을 결정이라 함은, 이를테면 제조 현장에서 설비의 노후, 문제 발생 예측, 제품의 불량 검출 등과 같은 이상 징후가 발생할 시 이를 조기에 발견한 후 스스로 문제를 해결하는 것을 의미한다. 본 논문에서는 제조 현장의 제조 공정 이상 징후 감지를 위해 대기행렬을 이용한 제조 공정 모델링을 제시하고 해당 모델링에서 이상 징후를 기계학습 기술 중 하나인 SVM을 이용하여 이를 감지하도록 한다. 해당 대기행렬을 M/D/1을 사용하였으며, ${\mu}$, ${\lambda}$, ${\rho}$를 기반으로 컨베이어 벨트 제조 시스템을 모델링하였다. SVM을 이용하여 ${\rho}$의 변화량을 통해 이상 징후를 감지했다.

• Journal of the Korean Wood Science and Technology
• /
• 제16권4호
• /
• pp.40-47
• /
• 1988

Our plywood manufacturing industries which entertained prosperous stage in late 1970's have come to be in face of the problems of conceedingly obtaining good quality logs and yield up-grading, which is considered by future-replaceable forest resources. In view of this point, manufacturing characteristic on softwood plywood using Japanese larch, pitch pine as domestic plantation species, and western hemlock as foreign species was studied. In this study, veneer- and plywood manufacturing yields were discussed in relation to log properties and veneer defects (knots). The summarized conclusions were as follows: 1. The majority of sample logs belonged to second grade on the standard. And, eccentricity of larch was the highest 11%, about 2 times those of pitch pine, hemlock. 2. Knot frequency of occurrence of larch reached 19% within log height 8m, and pitch pine 13% within 4m. Correspondingly, the log height of larch available for plywood manufacture was higher by about 2 times that of pitch pine. 3. In the knot types, most of knots of larch appeared dead, whereas those of pitch pine and hemlock appeared live. In size of knots, larch and hemlock showed relatively small 1-2cm dia. by 70% or more and pitch pine did the larger 24cm by 65%. Generally the more knot emerged in the inner side of veneer than the outer. 4. Plywood manufacturing yields by peeling with spindle revolution lathe were 37% in larch > 32% in hemlock> 26% in pitch pine. S. Jointed core veneer yields by peeling with outer perimeter back-up lathe were 55% in hemlock> 53% in larch> and 48% in pitch pine.

• 융합신호처리학회논문지
• /
• 제23권4호
• /
• pp.216-221
• /
• 2022

4차산업혁명은 사회 전반에 걸쳐 디지털 혁신으로의 전환을 가속화하고 있으며, 제조업에서는 스마트공장을 비롯해 4차산업혁명 기반 제조업 혁신을 위한 노력이 이어지고 있다. 제조업에서의 4차산업혁명 기술의 접목은 AI, 빅데이터, IoT, 클라우드, 로봇 등을 활용해 기존 자동화에서 업그레이드된 생산설비 데이터 수집 및 분석시스템 구축과 제품 불량 원인 파악 및 불량률을 최소화하기 위한 기술개발이 요구된다. 본 논문에서는 생산설비 현장에서의 전력, 환경, 설비 상태 데이터를 IoT 디바이스를 통해 수집하고, 수집한 데이터를 클라우드 컴퓨팅 환경에서 실시간으로 수치화하여 나타내고 위젯을 활용하여 MQTT기반 실시간 인포그래픽 형태로 표시할 수 있는 시스템을 구현하였다. IoT 디바이스로부터 전송된 실시간 센서 데이터를 Rest API 방식으로 클라우드 서버에 저장하고, 대시보드에서 데이터를 원격에서도 모니터링이 가능함은 물론 시간별, 일자별로 분석이 가능하였다.

• International Journal of Aeronautical and Space Sciences
• /
• 제17권1호
• /
• pp.109-119
• /
• 2016

When manufactured parts undergo large deformations during the manufacturing process, the global specifications of a part based on the concept of tolerance zone defined in the ISO 1101 standard [1] enable one to control the part's global defects. However, the extent of this tolerance zone is too large when the objective is to minimize local defects, such as hollows and bumps. Therefore, it is necessary to address local defects and global defects separately. This paper refers to the ISO 10579 standard [2] for flexible parts, which enables us to define a stressed state in order to measure the part by straightening it to simulate its position in the mechanism. The originality of this approach is that the straightening operation is performed numerically by calculating the displacement of a cloud of points. The results lead to a quantification of the global defects through various simple models and enable us to extract local defects. The outcome is an acceptable tolerance solution. The procedure is first developed for the simple example of a steel bar with a rectangular cross section, then applied to an industrial case involving a complex 3D surface of a turbine blade. The specification is described through ISO standards both in the free state and in the straightened state.

• 한국가구학회지
• /
• 제21권4호
• /
• pp.314-325
• /
• 2010

Shake and gnarl in the timber market are considered as a defect of reducing the quality of timber. However, this study expects that shake and gnarl are the optimum design tools to improve aesthetics of furniture if their unique form is properly used as formative expression factors of wooden furniture. This study is conducted to suggest methods in order for consumers and designers to consider shake and gnarl as new formative factors and apply them to wooden furniture designs. The study conducts a preference survey of general people by manufacturing furniture that has or doesn't have shake and gnarl, and measures the level of aesthetics after providing furniture design majors with furniture image that reprocesses shake and gnarl in a new way. According to the findings, shake and gnarl have latent aesthetic values, which verifies that various methods can be used to improve aesthetics of wooden furniture by means of a case study. By applying hidden authentic value of the verified shake and gnarl to furniture design, various improvement methods of aesthetics will have to be actively studied.

• 한국해양공학회지
• /
• 제17권4호
• /
• pp.31-36
• /
• 2003

In case of this thick rolling-steel for a multistory building, a large oil-drilling structure, a large vessel, a bridge and so on, Lamella Tearing around the welded joint zone is the most serious problems. In order to prevent Lamella Tearing, not only is choice of material important, but also the comprehensive investigation for the structural design and the construction. The Lamella Tearing that is a staircase-shape occurs due to the contraction stress to the thickness direction of the plate and has the character that the cracks progress along the elongated inclusion by rolling. In general, because cracks occur at the heat affected zone and around HAZ, it is necessary to establish the safety and the confidence of the welded structure to restrain the welding defect such as Lamella Tearing. The mechanical approaches are the easier and more economical than the approaches of the material and the construction method. In addition, the appropriate welding profile and the optimum welding condition contribute toward the improvement of the productivity and influence on the standardization of the manufacturing technology.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
• /
• pp.112-116
• /
• 2007

If any of the set parameters such as the environment temperature, mold temperature are not maintained at a consistent level, the fail rate of injection molding products is increased. The price of the injection molding machine is very high, so in order to maximize the utilization of the machine that is required the production of a number of different products with minimum fail rate using a single machine. To prevent the defect products by an inspection process with perfect quality is very important to minimizing production of defect products in the molding process. Vision inspection systems are widely utilized in various manufacturing industries for quality assurance purposes. The vision inspection system consists of CCD camera and lighting system to capture the image of the subject of inspection, an image comparison algorithm using to determine the pass/fail of the products, and mechanical devices for the operation of the whole system. This research focuses on the development of the vision inspection system to process the inspection of an automobile parts. We developed a mechanical devices for the inspection of the injection molding products and an image comparison algorithm to determine the pass/fail result of the inspection based on the molding image and the accepted product image.

• 대한안전경영과학회지
• /
• 제18권1호
• /
• pp.111-118
• /
• 2016

KC Mark is one of the country's integrated legal force to the minimum mandatory certification mark system for safety. That is absolutely needed for manufacturing and sales of goods in Korea. This thesis intended to see what is prevalent for both imports and domestic products for illegal and defect and rebuild the ecosystem as soon as possible for the healthy development through public awareness. In this theses point out the seriousness of the problem based on the various kinds of press releases, data of KCA(Korea Consumer Agency), MOTIE(Ministry of Trade, Industry and Energy) and KCA(Korea Customs Service) to the problem of certification system of KC mark and propose a solution to that issue. This study is considered to make befit the nation's place in the world and sustainable development is possible about the system of certification KC. This study expect more research on this issue in order to make enhance the confidence of KC mark.

• 제어로봇시스템학회논문지
• /
• 제15권8호
• /
• pp.761-771
• /
• 2009

Detecting defects on FPD (Flat Panel Display) color filter before the full panel is made is important to reduce the manufacturing cost. Among many types of defects, the low contrast blemish such as Suzi Mura is difficult to detect using standard CCD cameras. Even skilled inspectors in the inspection line can hardly identify such defects using bare eyes. To overcome this difficulty, point spectrometer has been used to analyze the spectrum to differentiate such defects from normal color filters. However, scanning ever increasing-size color filters by a point spectrometer takes too long time to be used in real production line. We propose a system using a spectral camera which can be viewed as a line scan camera composed of an array of point spectrometers. Three types of lighting system that exhibit different illumination spectrums are devised together with a calibration method of the proposed spectral camera system. To visualize the defect areas, various processing algorithms to identify and to enhance the small differences in spectrum between defective and normal areas are developed. Experiments shows 85% successful visualization. of real samples using the proposed system.